Sergei Alexander Schelkunoff (; January 27, 1897 – May 2, 1992), who published as S. A. Schelkunoff, was a distinguished

mathematician A mathematician is someone who uses an extensive knowledge of mathematics in their work, typically to solve mathematical problems. Mathematicians are concerned with numbers, data, quantity, mathematical structure, structure, space, Mathematica ...

electrical engineer Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems that use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the l ...

, and

electromagnetism In physics, electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature. It is the dominant force in the interacti ...

theorist who made noted contributions to

antenna theory In radio-frequency engineering, an antenna (American English) or aerial (British English) is an electronic device that converts an alternating electric current into radio waves (transmitting), or radio waves into an electric current (receivi ...

Biography

Schelkunoff was born in

Samara Samara, formerly known as Kuybyshev (1935–1991), is the largest city and administrative centre of Samara Oblast in Russia. The city is located at the confluence of the Volga and the Samara (Volga), Samara rivers, with a population of over 1.14 ...

, Russia in 1897, attended the

University of Moscow Moscow State University (MSU), officially M. V. Lomonosov Moscow State University,. is a public research university in Moscow, Russia. The university includes 15 research institutes, 43 faculties, more than 300 departments, and six branches. Al ...

before being drafted in 1917. He crossed

Siberia Siberia ( ; , ) is an extensive geographical region comprising all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has formed a part of the sovereign territory of Russia and its predecessor states ...

into

Manchuria Manchuria is a historical region in northeast Asia encompassing the entirety of present-day northeast China and parts of the modern-day Russian Far East south of the Uda (Khabarovsk Krai), Uda River and the Tukuringra-Dzhagdy Ranges. The exact ...

and then

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

before settling in

Seattle Seattle ( ) is the most populous city in the U.S. state of Washington and in the Pacific Northwest region of North America. With a population of 780,995 in 2024, it is the 18th-most populous city in the United States. The city is the cou ...

in 1921. There he received bachelor's and master's degrees in mathematics from the State College of Washington, now

Washington State University Washington State University (WSU, or colloquially Wazzu) is a Public university, public Land-grant university, land-grant research university in Pullman, Washington, United States. Founded in 1890, WSU is also one of the oldest Land-grant uni ...

, and in 1928 received his Ph.D. from

Columbia University Columbia University in the City of New York, commonly referred to as Columbia University, is a Private university, private Ivy League research university in New York City. Established in 1754 as King's College on the grounds of Trinity Churc ...

for his dissertation ''On Certain Properties of the Metrical and Generalized Metrical Groups in Linear Spaces of Dimension''. After receiving his degree, Schelkunoff joined

Western Electric Western Electric Co., Inc. was an American electrical engineering and manufacturing company that operated from 1869 to 1996. A subsidiary of the AT&T Corporation for most of its lifespan, Western Electric was the primary manufacturer, supplier, ...

's research wing, which became

Bell Laboratories Nokia Bell Labs, commonly referred to as ''Bell Labs'', is an American industrial research and development company owned by Finnish technology company Nokia. With headquarters located in Murray Hill, New Jersey, the company operates several lab ...

. In 1933 he and Sally P. Mead began analysis of

waveguide A waveguide is a structure that guides waves by restricting the transmission of energy to one direction. Common types of waveguides include acoustic waveguides which direct sound, optical waveguides which direct light, and radio-frequency w ...

propagation discovered analytically by their colleague

George C. Southworth George Clark Southworth (August 24, 1890 – July 6, 1972), who published as G. C. Southworth, was a prominent American radio engineer best known for his role in the development of waveguides in the early 1930s. Biography Southworth was born in ...

. Their analysis uncovered the

transverse mode A transverse mode of electromagnetic radiation is a particular electromagnetic field pattern of the radiation in the plane perpendicular (i.e., transverse) to the radiation's propagation direction. Transverse modes occur in radio waves and micr ...

s. Schelkunoff appears to have been the first to notice the important practical consequences of the fact that attenuation in the TE01 mode decays inversely with the power of the frequency. In 1935 he and his colleagues reported that

coaxial cable Coaxial cable, or coax (pronounced ), is a type of electrical cable consisting of an inner Electrical conductor, conductor surrounded by a concentric conducting Electromagnetic shielding, shield, with the two separated by a dielectric (Insulat ...

, then new, could transmit

television Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...

pictures or up to 200

telephone A telephone, colloquially referred to as a phone, is a telecommunications device that enables two or more users to conduct a conversation when they are too far apart to be easily heard directly. A telephone converts sound, typically and most ...

conversations. During his 35 year career at Bell Labs, Schelkunoff's research included

radar Radar is a system that uses radio waves to determine the distance ('' ranging''), direction ( azimuth and elevation angles), and radial velocity of objects relative to the site. It is a radiodetermination method used to detect and track ...

electromagnetic wave In physics, electromagnetic radiation (EMR) is a self-propagating wave of the electromagnetic field that carries momentum and radiant energy through space. It encompasses a broad spectrum, classified by frequency or its inverse, wavelength, ...

propagation in the atmosphere and in microwave guides,

short-wave radio Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). There is no official definition of the band range, but it always includes all of the high frequency band (HF), which extends from 3 to 30 MHz (app ...

, broad-band antennas, and grounding. He taught for five years at

, and later served as assistant director of mathematical research and assistant vice president for university relations. He retired from Columbia U. in 1965, and served as a consultant on

magnetron The cavity magnetron is a high-power vacuum tube used in early radar systems and subsequently in microwave oven, microwave ovens and in linear particle accelerators. A cavity magnetron generates microwaves using the interaction of a stream of ...

s for the United States Naval Station at

San Diego San Diego ( , ) is a city on the Pacific coast of Southern California, adjacent to the Mexico–United States border. With a population of over 1.4 million, it is the List of United States cities by population, eighth-most populous city in t ...

. Schelkunoff received 15 patents, the

IEEE Morris N. Liebmann Memorial Award The initially called Morris Liebmann Memorial Prize provided by the Institute of Radio Engineers (IRE), the IEEE Morris N. Liebmann Memorial Award was created in 1919 in honor of Colonel Morris N. Liebmann. It was initially given to awardees who h ...

from the

Institute of Radio Engineers The Institute of Radio Engineers (IRE) was a professional organization which existed from 1912 until December 31, 1962. On January 1, 1963, it merged with the American Institute of Electrical Engineers (AIEE) to form the Institute of Electrical ...

(1942), and the

Franklin Institute The Franklin Institute is a science museum and a center of science education and research in Philadelphia, Pennsylvania. It is named after the American scientist and wikt:statesman, statesman Benjamin Franklin. It houses the Benjamin Franklin ...

Stuart Ballantine Medal {{Refimprove, date=February 2018 The Stuart Ballantine Medal was a science and engineering award presented by the Franklin Institute, of Philadelphia, Pennsylvania, USA. It was named after the US inventor Stuart Ballantine. Laureates *1947 - Ge ...

(1949). He died on 2 May 1992, in

Hightstown, New Jersey Hightstown is a Borough (New Jersey), borough in Mercer County, New Jersey, Mercer County, in the U.S. state of New Jersey. Nestled within the Raritan River, Raritan Valley region, Hightstown is an historic, commercial, and cultural hub of Cent ...

Selected works

Articles

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Books

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Patents

* – ''Ultra short wave radio system'' –

References

Other sources

* * * * {{DEFAULTSORT:Schelkunoff, Sergei Alexander 1897 births 1992 deaths Scientists from Samara, Russia People from Samarsky Uyezd Russian military personnel of World War I White Russian emigrants to the United States 20th-century American mathematicians 20th-century American engineers Microwave engineers American telecommunications engineers American electrical engineers Moscow State University alumni Columbia University faculty Columbia School of Engineering and Applied Science faculty Scientists at Bell Labs